Liquid-absorbing sheet for animal litter box

ABSTRACT

An animal litter box system that can be used for a long time about 3 to 10 days and can prevent the occurrence of undesirable odors is to be provided, particularly to provide a liquid-absorbing sheet used for the animal litter box system. A liquid-absorbing sheet used for an animal litter box is characterized by comprising an antimicrobial and bacteriostatic part having both an antimicrobial property and a bacteriostatic property; or both of an antimicrobial part having an antimicrobial property and a bacteriostatic part having a bacteriostatic property.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a liquid-absorbing sheet usedfor an animal litter box.

[0003] 2. Description of the Related Art

[0004] For an animal litter box used by pets such as cats kept in roomsto evacuate urine or feces in a room, a product described in Japaneseun-examined patent publication JP-10-229768-A is named, for example. Theanimal litter box described in JP-10-229768-A is that a plurality ofwater repellent granular materials is placed in a container having abottom part with a bottom sheet which has a liquid passing structure. Anabsorbing sheet supported by a support body is disposed under the bottomsheet of the container in close contact with the bottom sheet.

[0005] In this animal litter box, urine passes through among the waterrepellent granular materials and through the bottom part of thecontainer, and then is absorbed into the absorbing sheet. Therefore,urine does not remain in the container, and the litter box is cleanedonly by changing the liquid-absorbing sheet once a day. In addition, itis fine that the granular materials soiled with urine or feces arechanged once a month or two months.

[0006] However, since the animal litter box described in Patent Documentmentioned above has a premise that the liquid-absorbing sheet is changedonce a day, waste is generated everyday even though it occurs once aday, being troublesome. Furthermore, since the bottom part of thecontainer on which the granular materials are placed is very close tothe absorbing sheet, urine returns back when an absorbed amount isincreased by long time use, which causes a problem that long time use isnot allowed. Moreover, since the granular materials are water repellentwith no liquid absorption, moisture of feces cannot be removed as wellas urine remains around the granular materials and become rotten, whichcauses a problem that undesirable odors occur as well. Therefore, aproblem for the time being is to provide an animal litter box systemthat can prevent the occurrence of undesirable odors from animalexcrement of animals, especially pet animals, and can save the troubleof changing the liquid-absorbing sheet and the granular materials asmuch as possible for long time use.

SUMMARY OF THE INVENTION

[0007] The present invention has been made in view of the problemsmentioned above. An object of the present invention is to provide ananimal litter box system that can be used for a long time about 3 to 10days and can prevent the occurrence of undesirable odors, particularlyto provide a liquid-absorbing sheet used for the animal litter boxsystem.

[0008] In order to achieve the object, the inventors diligentlyinvestigated and made the present invention. More specifically, thepresent invention is to provide the following.

[0009] (1) A liquid absorptive liquid-absorbing sheet for an animallitter box comprising an antimicrobial and bacteriostatic part havingboth an antimicrobial property and a bacteriostatic property; or both ofan antimicrobial part having an antimicrobial property and abacteriostatic part having a bacteriostatic property.

[0010] According to the invention described in (1), since theliquid-absorbing sheet has an antimicrobial property, it can inhibit thegrowth and proliferation of microbes such as bacterium and fungus.Therefore, it can prevent the occurrence of undesirable odors and canreduce a sickening sense in changing the liquid-absorbing sheet, andalso can be used for a long time.

[0011] Moreover, since the liquid-absorbing sheet has also abacteriostatic property, it can reduce the growth and proliferation ofmicrobes and can neutralize ammonia generated from rotten urine.Therefore, the liquid-absorbing sheet can prevent the occurrence ofundesirable odors and can reduce a sickening sense in-changing theliquid-absorbing sheet, and also can be used for a long time.

[0012] Here, the ‘antimicrobial property’ means that the growth andproliferation of microbes is inhibited, and the ‘bacteriostaticproperty’ means that the growth or proliferation of microbes is subduedin this specification.

[0013] (2) The liquid-absorbing sheet for the animal litter boxaccording to (1), wherein the antimicrobial property is imparted by acationic surfactant being contained.

[0014] According to the invention described in (2), the cationicsurfactant is used as an ingredient to impart the antimicrobialproperty, preferably didecyldimethylammonium adipate is used. Sincedidecyldimethylammonium adipate is safer than the other typicalingredients to impart the antimicrobial property in oral toxicity andskin irritation, it is preferably used.

[0015] (3) The liquid-absorbing sheet for the animal litter boxaccording to (1) or (2), wherein the bacteriostatic property is impartedby an organic acid being contained.

[0016] According to the invention described in (3), undesirable odorscan be lessened by using the organic acid as an ingredient to impart thebacteriostatic property, which can neutralize ammonia generated fromrotten urine. Among the organic acids, citric acid is a crystal, andthus it is preferably used in view of the productivity of theliquid-absorbing sheet.

[0017] (4) The liquid-absorbing sheet for the animal litter boxaccording to any one of (1) to (3), wherein the antimicrobial propertyis imparted by an ingredient to impart the antimicrobial property, and0.1 g or more of the ingredient to impart the antimicrobial property iscontained per liquid-absorbing sheet.

[0018] According to the invention described in (4), since 0.1 g or moreof the ingredient to impart the antimicrobial property is contained pera liquid-absorbing sheet, the occurrence of undesirable odors can beprevented effectively even though the liquid-absorbing sheet is used fora long time. However, when the ingredient to impart the antimicrobialproperty is contained excessively, it is not preferable because aproblem arises in safety in case where a pet eats it. Furthermore, thereis not much difference in an advantage to be obtained even though theingredient to impart the antimicrobial property is containedexcessively.

[0019] (5) The liquid-absorbing sheet for the animal litter boxaccording to any one of (1) to (4), wherein the bacteriostatic propertyis imparted by an ingredient to impart the bacteriostatic property, and0.1 to 10.0 g of the ingredient to impart the bacteriostatic property iscontained per liquid-absorbing sheet.

[0020] According to the invention described in (5), since 0.1 to 10.0 gof the ingredient to impart the bacteriostatic property is contained perliquid-absorbing sheet, the liquid-absorbing sheet can neutralizeammonia generated from rotten urine and can prevent the occurrence ofundesirable odors. It is preferable that the ingredient to impart thebacteriostatic property is contained 0.25 to 1.0 g per liquid-absorbingsheet. It is not preferable that the content of the ingredient to impartthe bacteriostatic property is too much, because pH is reducedexcessively to cause the water absorptive property of the superabsorbent polymer comprising the liquid-absorbing sheet to be lowered.The liquid absorbed into the liquid-absorbing sheet might return back tothe front surface of the liquid-absorbing sheet depending on thecircumstances.

[0021] (6) The liquid-absorbing sheet for the animal litter boxaccording to anyone of (1) to (5), wherein the liquid-absorbing sheethas an area of 2000 cm² or below, a thickness of 1.5 to 5.0 mm, and awater retention capacity of 400 g or greater.

[0022] According to the invention described in (6), since theliquid-absorbing sheet has an area of 2000 cm² or below, a thickness of1.5 to 5.0 mm, and a water retention capacity of 400 g or greater, ithas sufficient water absorptive capacity, and can be used for a longtime. Here, the ‘water retention capacity’ means an amount of liquidheld after the liquid-absorbing sheet having been immersed inphysiological salt solution for 10 minutes is suspended for 10 minutesand is dehydrated by a dehydrater of 150 G for 90 seconds.

[0023] (7) The liquid-absorbing sheet for the animal litter boxaccording to any one of (1) to (6), wherein the liquid-absorbing sheethas a liquid permeable front layer, a liquid impermeable back layer, andan absorption layer with liquid absorptive property sandwiched betweenthe front layer and the back layer, and the antimicrobial andbacteriostatic part, or the antimicrobial part and/or the bacteriostaticpart is disposed in the absorption layer.

[0024] According to the invention described in (7), the liquid-absorbingsheet can suppress the occurrence of undesirable odors more effectivelythan (1) and can be used for a long time. For example, when two or moreof the absorption layers are disposed separately and the antimicrobialand bacteriostatic part, or the antimicrobial part and/or thebacteriostatic part is sandwiched between the absorption layers liquideasily move downward to improve the water absorptive property ascompared with the case where the absorption layer is a single layer.Furthermore, an antimicrobial agent irritant to skin can be preventedfrom exuding to the surface, and a powder bacteriostatic agent can befixed in the liquid-absorbing sheet. Moreover, when the absorption layeris a single layer, the thickness of the layer is increased in order tosecure the water retention capacity required for the present invention,and the water absorptive property is reduced by inhibiting a superabsorbent polymer from meeting liquid. However, it can be avoided bydisposing two or more of the absorption layers separately.

[0025] (8) The liquid-absorbing sheet for the animal litter boxaccording to (7), wherein the liquid permeable front layer is white.

[0026] According to the invention described in (8), the liquid permeablefront layer is white to allow the amount and color of pet's urine to beknown and then the health condition of the pet to be known. At present,commercially available pet sheets have a colored absorbing surface fordiscriminating between the front side and the back side of the sheets.Therefore, the advantage to know the health condition of pets is anunprecedented new advantage created by the present invention.

[0027] (9) The liquid-absorbing sheet for the animal litter boxaccording to (7) or (8), wherein the liquid impermeable back layer iscolored.

[0028] According to (9), the liquid impermeable back layer is colored,which can discriminate between the front side and the back side of theliquid-absorbing sheet and prevent the occurrence of a mistake in use.

[0029] (10) The liquid-absorbing sheet for the animal litter boxaccording to any one of (7) to (9), wherein the liquid permeable frontlayer and/or the liquid impermeable back layer has an indication toallow discrimination between a front side and a back side.

[0030] According to (10), the liquid permeable front layer and/or theliquid impermeable back layer has the indication to allow thediscrimination between the front side and the back side, and an error tomistake the front side for the back side in use can be preventedeffectively. For the indication, patterns, company names, and housemarks can be provided in addition to letters like these, allowing theprovision of advertising effects. For example, it is fine to print‘FRONT SIDE’ on the liquid permeable front layer so as not to fadecolor.

[0031] (11) An animal litter box comprising a granular materialcontainer having an opening for an animal going in and out, a liquidpassing bottom part on which granular materials are dispersed, and aliquid-absorbing sheet holder placed under the bottom part of thegranular material container on which the liquid-absorbing sheet isplaced, wherein the liquid-absorbing sheet is the liquid-absorbing sheetin any one of (1) to (10).

[0032] According to the invention described in (11), theliquid-absorbing sheet according to the present invention is used alongwith the granular materials having a high liquid passing property and aliquid absorptive property in the animal litter box comprising theopening for an animal going in and out, the granular material holderhaving the liquid passing bottom part on which the granular materialsare dispersed, and the liquid-absorbing sheet holder placed under thebottom part of the granular material container on which theliquid-absorbing sheet is placed. When the liquid-absorbing sheetaccording to the present invention is used for the animal litter boxsystem like this, an animal litter which can be used for a long timeabout 3 to 10 days is provided.

BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The teachings of the present invention can be readily understoodby considering the following detailed description in conjunction withthe accompanying drawings, in which:

[0034]FIG. 1 is a cross-sectional view illustrating a first embodimentof the liquid-absorbing sheet according to the present invention;

[0035]FIG. 2 is a cross-sectional view illustrating a second embodimentof the liquid-absorbing sheet according to the present invention;

[0036]FIG. 3 is a diagram illustrating a mode to use theliquid-absorbing sheet according to the present invention; and

[0037]FIG. 4 is a diagram illustrating the relationship between the pHand the water absorption and retention of a super absorbent polymer usedfor the liquid-absorbing sheet according to the present invention.

DETAILED DESCRIPTION OF THE INVENTION

[0038] Hereinafter, embodiments of the present invention will bedescribed with reference to the drawings. Additionally, in thedescription of a second embodiment, the description of the sameconfiguration and advantages as those of a first embodiment is omitted.

FIRST EMBODIMENT

[0039] [Total Configuration of the Liquid-absorbing Sheet]

[0040]FIG. 1 is a cross-sectional view illustrating a first embodimentof the liquid-absorbing sheet according to the present invention. Aliquid-absorbing sheet 1 has an area of 2000 cm² or below and athickness of 1.5 to 5.0 mm, and has water-absorptive property that awater retention capacity is 400 g or greater. The liquid-absorbing sheet1 has a liquid permeable front layer 11, a liquid impermeable back layer17, and an upper absorption layer 18 and a lower absorption layer 19having liquid absorptive capacity. The upper absorption layer 18 and thelower absorption layer 19 are sandwiched between the liquid permeablefront layer 11 and the liquid impermeable back layer 17. The liquidpermeable front layer 11 is white, and the liquid impermeable back layer17 is colored. An antimicrobial part 14 and a bacteriostatic part 13contacting each other form an antimicrobial and bacteriostatic part 15which is sandwiched between the upper absorption layer 18 and the lowerabsorption layer 19. Both of the upper absorption layer 18 and the lowerabsorption layer 19 contain pulp and a super absorbent polymer. An upperlayer tissue 12 is sandwiched between the upper absorption layer 18 andthe liquid permeable front layer 11, and an under layer tissue 16 issandwiched between the lower absorption layer 19 and the liquidimpermeable back layer 17. The upper layer tissue 12 and the under layertissue 16 are white.

[0041] [Antimicrobial Part]

[0042] The antimicrobial part 14 contains an ingredient which imparts anantimicrobial property (hereinafter, it is called an ingredientimparting antimicrobial property). As the ingredient impartingantimicrobial property, didecyldimethylammonium adipate is used amongcationic surfactants, but the other cationic surfactants are usable, notlimited to this. Didecyldimethylammonium adipate is preferably usedbecause it is highly safer than the other typical ingredients impartingantimicrobial property in oral toxicity and skin irritation.

[0043] A content of the ingredient imparting antimicrobial property is0.1 g or more per liquid-absorbing sheet. This content is enough toimpart the antimicrobial property to the liquid-absorbing sheet. Asdescribed above, when the ingredient imparting antimicrobial property isexcessively contained, it is not preferable because a problem arises insafety in case where a pet eats it. Furthermore, there is not muchdifference in the advantage to be obtained even though the ingredient toimpart the antimicrobial property is contained excessively.Additionally, the amount of the ingredient imparting antimicrobialproperty used per unit is 1 to 10 g/m².

[0044] [Bacteriostatic Part]

[0045] The bacteriostatic part 13 contains an ingredient which imparts abacteriostatic property (hereinafter, it is called an ingredientimparting bacteriostatic property). For the ingredient impartingbacteriostatic property, citric acid is used among organic acids, butthe other organic acids are usable, not limited to this. Since citricacid is a crystal, it is preferably used in view of productivity of theliquid-absorbing sheet.

[0046] A content of the ingredient imparting bacteriostatic property is0.1 to 10.0 g per liquid-absorbing sheet, preferably 0.25 to 1.0 g. FIG.4 is a diagram illustrating the relationship between the relationshipbetween the pH and the water absorption ratio of a super absorbentpolymer. The horizontal axis indicates the pH and the vertical axisindicates the water absorption ratio (times) of the super absorbentpolymer. When the content of the ingredient imparting bacteriostaticproperty is too much, pH is lowered. As shown in FIG. 4, when pH islowered, the water-absorption capacity of the super absorbent polymer isreduced. Additionally, the amount of the ingredient impartingbacteriostatic property used per unit is 5 to 50 g/m².

[0047] [Absorption Layer]

[0048] In this embodiment, there are two absorption layers; the upperabsorption layer 18 and the lower absorption layer 19. Both of theabsorption layers have pulp and a super absorbent polymer. As describedabove, two or more of absorption layers are separately disposed in thismanner, which allows liquid to easily move downward to improvewater-absorption capacity as compared with the case where the absorptionlayer is a single layer. Furthermore, when the absorption layer is asingle layer, the thickness of the layer is increased in order to securethe water retention capacity required in the invention, and it becomeshard for the super absorbent to meet water. Consequently, the waterabsorption capacity is sometimes reduced. In this point, two or more ofabsorption layers is preferable to be disposed separately.

[0049] The super absorbent polymer exists among the crushed pulp insidethe upper absorption layer 18 and the lower absorption layer 19. As thesuper absorbent polymer, polymers having high absorptive capacity suchas starch-acrylic polymers are generally used other than polyacrylicpolymers. These absorption layers are formed by layering crushed pulpand then applying a super absorbent polymer thereto.

[0050] In the upper absorption layer 18, the amount of pulp used perunit is 50 to 150 g/m², and the amount of super absorbent polymer usedper unit is 30 to 100 g/m². Furthermore, in the lower absorption layer19, the amount of pulp used per unit is 150 to 300 g/m^(2,) and theamount of a super absorbent polymer used per unit is 30 to 200 g/m².Moreover, the total content of pulp contained in the absorption layer(which is comprised of both the upper absorption layer 18 and the lowerabsorption layer 19) is 200 to 450 g/m², and the total content of asuper absorbent polymer contained in the absorption layer is 60 to 600g/m².

[0051] [Liquid Permeable Front Layer and Liquid Impermeable Back Layer]

[0052] For the liquid permeable front layer 11, nonwoven fabric such asthrough air, span lace, span bond, and polypropylene point bond nonwovenfabric are used. For the liquid impermeable back layer 17, polyethylene,polypropylene, and polyethylene terephthalate are used.

[0053] Since the liquid permeable front layer 11 is white, the amountand color of pet's urine can be known, and then the health condition ofthe pet can be known.

[0054] The liquid impermeable back layer 17 is colored. As describedabove, since the liquid permeable front layer 11 is white, the liquidimpermeable back layer 17 is colored to discriminate between the frontside and the back side.

[0055] Furthermore, the liquid permeable front layer 11 and/or theliquid impermeable back layer 17 can have an indication to discriminatebetween the front side and the back side as well. When the indication todiscriminate between the front side and the back side is provided, anerror to mistake the front side for the back side can be prevented inuse.

[0056] [Mode of Usage]

[0057]FIG. 3 is a mode to use the liquid-absorbing sheet according tothe present invention. The liquid-absorbing sheet 1 according to thepresent invention is used along with granular materials 34 for an animallitter box 10. The animal litter box 10 has a cover 33 for controlling(defining) the entrance for pets, a granular material container 32having a liquid passing bottom part on which the granular materials aredispersed, and a liquid-absorbing sheet holder 31 placed under thebottom part of the granular material container 32. The liquid-absorbingsheet 1 is placed on the liquid-absorbing sheet holder 31.

[0058] The granular materials 34 are silica gel having a character ofhigh liquid passing property and a liquid absorptive property. Theanimal litter box shown in FIG. 3 has a liquid leading part shaped byserial arch shapes in the bottom part on the side facing theliquid-absorbing sheet 1.

[0059] [Advantage of the First Embodiment]

[0060] In the liquid-absorbing sheet of the first embodiment, theabsorption layer is separated to the upper absorption layer 18 and thelower absorption layer 19 and the upper and lower absorption layers aredisposed separately on the front and back sides of the antimicrobial andbacteriostatic part 15 which is comprised of the antimicrobial part 14and the bacteriostatic part 13 contacting each other. In this manner,two absorption layers are separately disposed to allow liquid to movedownward to improve water-absorptive capacity as compared with the casewhere the absorption layer is a single layer.

[0061] Furthermore, the antimicrobial and bacteriostatic part 15 whichis comprised of the antimicrobial part 14 and the bacteriostatic part 13contacting each other is sandwiched between the upper absorption layer18 and the lower absorption layer 19. Thus, it provides advantages thatthe liquid absorbing sheet 1 can prevent the ingredient impartingantimicrobial property irritant to human skin from exuding to thesurface and fix a powder ingredient imparting bacteriostatic property inthe liquid-absorbing sheet.

[0062] Since the ingredient imparting antimicrobial property iscontained in the liquid-absorbing sheet, the occurrence of undesirableodors can be prevented effectively, and the liquid-absorbing sheet canbe used for a long time.

[0063] Furthermore, since the citric acid is also contained in theliquid-absorbing sheet as the ingredient imparting bacteriostaticproperty, ammonia generated by rotten urine can be neutralized toprevent the occurrence of offensive odors. Moreover, the ingredientimparting bacteriostatic property has a function of a pH control agentto suppress a pH increase by neutralization reaction with ammonia. Asapparent from the relationship between the pH and the water absorptiveproperty of the super absorbent polymer shown in FIG. 4, the waterabsorptive property of the super absorbent polymer used for theabsorption layer depends on pH, and a pH increase reduces the waterabsorptive property of the super absorbent polymer. Therefore, theingredient imparting bacteriostatic property has an advantage tosuppress a reduction in the water absorptive property of the superabsorbent polymer as well.

[0064] The provision of the liquid-absorbing sheet according to thepresent invention in the mode shown in FIG. 3 allows pet's urine tosmoothly move to the liquid-absorbing sheet for absorption. Therefore,an animal litter box system can be used for a long time and can preventthe occurrence of undesirable odors.

SECOND EMBODIMENT

[0065] [Total Configuration of the Liquid-absorbing Sheet]

[0066]FIG. 2 is a cross-sectional view illustrating a second embodimentof a liquid-absorbing sheet according to the present invention. A liquidpermeable front layer 11, a liquid impermeable back layer 17, an upperlayer tissue 12, and an under layer tissue 16 are the same as those inthe first embodiment. The difference from the first embodiment is inthat an absorption layer 20 in the second embodiment is a mixture of anantimicrobial part, a bacteriostatic part and the upper absorption layeror lower absorption layer of the first embodiment. More specifically,the absorption layer 20 of the second embodiment contains theantimicrobial part and the bacteriostatic part as well as pulp and asuper absorbent polymer. Even though the absorption layer is formed as asingle layer in the second embodiment, there is no problem as long asthe water retention capacity required in the invention can be secured.

[0067] [Advantage of the Second Embodiment]

[0068] In addition to the same advantages as those in the firstembodiment, there is an advantage that the liquid-absorbing sheet isfabricated easier than in the first embodiment.

EXAMPLE

[0069] Hereinafter, an example of the first embodiment according to thepresent invention will be described, but the invention is not limited tothe example.

[0070] The liquid-absorbing sheet of the first embodiment according tothe invention was fabricated as below.

[0071] (A) First, crushed pulp was layered on an under layer tissue, anda polyacrylic super absorbent polymer was dispersed thereon to form alower absorption layer. Furthermore, didecyldimethylammonium adipate asthe ingredient imparting antimicrobial property and citric acid as theingredient imparting bacteriostatic property were sequentially dispersedon the formed lower absorption layer to form an antimicrobial part and abacteriostatic part.

[0072] (B) Subsequently, crushed pulp was layered on an upper layertissue, and then a polyacrylic super absorbent polymer was dispersedthereon to form an upper absorption layer. (C) Products obtained by (A)and (B) were joined so as to contact the bacteriostatic part with theupper absorption layer, polypropylene point bond nonwoven fabric wasplaced on the upper layer tissue as a liquid permeable front layer, andthen polyethylene was placed under the under layer tissue as a liquidimpermeable back layer to obtain a liquid-absorbing sheet.

[0073] The liquid-absorbing sheet obtained by the method mentioned abovewas used along with granular materials having a high liquid passingproperty and a liquid absorptive property in an animal litter box whichhas a granular material container having an opening for an animal goingin and out and a liquid passing bottom part on which the granularmaterials are dispersed, a liquid-absorbing sheet holder placed underthe bottom part of the granular material container on which theliquid-absorbing sheet was placed. Accordingly, an animal litter boxsystem cloud be used for a long time and could prevent the occurrence ofoffensive odors.

[0074] As described above, the liquid-absorbing sheet according to thepresent invention has the antimicrobial and bacteriostatic part havingboth the antimicrobial property and the bacteriostatic property, or hasboth the antimicrobial part having the antimicrobial property and thebacteriostatic part having the bacteriostatic property. Therefore, itcan prevent the occurrence of offensive odors even though it is used fora long time.

[0075] Furthermore, the liquid-absorbing sheet according to theinvention has an area of 2000 cm² or below, a thickness of 1.5 to 5.0mm, and a water retention capacity is 400 g or greater. Thus, it hassufficient water absorptive capacity, and can be used for a long time.

[0076] Moreover, the liquid-absorbing sheet according to the presentinvention is used along with the granular materials having a high liquidpassing property and a liquid absorptive property in the animal litterbox which has a granular material container having an opening for ananimal going in and out and a liquid passing bottom part on which thegranular materials are dispersed, the liquid-absorbing sheet holderplased under the bottom part of the granular material container on whichthe liquid-absorbing sheet is placed. Therefore, the animal litter boxsystem can be used for a long time and can prevent the occurrence ofoffensive odors.

1. An animal litter box comprising: a granular material container havingan opening for an animal going in and out, and a liquid passing bottompart on which granular materials are dispersed; and a liquid-absorbingsheet holder placed under the bottom part of the granular materialcontainer on which a liquid-absorbing sheet is placed, wherein thebottom part of the granular material container has a liquid leading partformed by connected arches on a side facing the liquid-absorbing sheet.2. The animal litter box according to claim 1, wherein the bottom partis grid ironed having a plurality of opening parts, and the opening parthas dimensions smaller than those of the granular material.
 3. Theanimal litter box according to claim 2, wherein an open area ratio ofthe opening of the bottom part occupied by the opening parts is 25 to50% of an area of the bottom part.
 4. The animal litter box according toclaim 1, wherein the bottom part is detachable from the granularmaterial container.
 5. The animal litter box according to claim 1,wherein the liquid-absorbing sheet has an area greater than that of thebottom part of the granular material container.
 6. The animal litter boxaccording to claim 1, wherein the liquid-absorbing sheet holder isloadably incorporated under the bottom part of the granular materialcontainer.
 7. The animal litter box according to claim 1, wherein theanimal litter box has a drawer structure that can house a drawer body,and the liquid-absorbing sheet holder is the drawer body.
 8. The animallitter box according to claim 7, wherein the animal litter box has adrawer structure that can house a drawer body, and the liquid-absorbingsheet holder is the drawer body.
 9. The animal litter box according toclaim 1, wherein the animal litter box has a cover for controlling adirection of an animal going in and out mounted detachably.
 10. Theanimal litter box according to claim 9, wherein a granular materialdropper is detachably disposed at a position facing an opening of thecover in the animal litter box.
 11. The animal litter box according toclaim 10, wherein the granular material dropper includes a granularmaterial removing member having a mesh top plate, and a granularmaterial recovery container disposed under the granular materialremoving member.
 12. The animal litter box according to claim 1, whereinthe granular materials has a liquid absorptive capacity wherein amaximum absorbable amount of liquid absorbed by each of the granularmaterials is 0.3 to 4.0 times as much as its own weight and an amount ofliquid absorbed by each of the granular materials per three second is 20to 70% of the maximum absorbable amount of liquid absorbed by each ofthe granular materials and has a liquid passing ratio of a mass of thegranular materials is 70% or more.
 13. The animal litter box accordingto claim 1, wherein the liquid-absorbing sheet has an antimicrobial andbacteriostatic part having both an antimicrobial property and abacteriostatic property, or both of an antimicrobial part having anantimicrobial property and a bacteriostatic part having a bacteriostaticproperty.